What is the unique ID number coordinated by the IEEE used by network interface cards?

The unique ID number coordinated by the IEEE and used by network interface cards is the Media Access Control address, commonly known as the MAC address. The MAC address is a unique identifier assigned to network interfaces for communications on the physical network segment.

This address is crucial for network protocols as it helps to ensure that data packets are delivered to the correct device in a local network. The uniqueness of the MAC address is maintained because it is assigned by the manufacturer and is embedded into the hardware of the network interface card (NIC). Each NIC typically has a unique MAC address, which facilitates proper identification and communication within local area networks (LANs).

The other options refer to different types of identification or addressing used in networking. For example, the Internet Protocol Address (IP) is used for routing traffic across the internet and is not specific to the hardware. The Network Identifier and Device Identification Number do not refer to standardized identifiers in the context of network interfaces. Thus, the MAC address is the correct choice as it specifically aligns with the IEEE standard for network interface identification.